Printable Filament Spool Hub Skips The Bearings

March 16, 2019 by Tom Nardi 32 Comments

When you really start fine-tuning your 3D printer, you might start to notice that even the smallest things can have a noticeable impact on your prints. An open window can cause enough of a draft to make your print peel up from the bed, and the slightly askew diameter of that bargain basement filament can mess up your extrusion rate. It can be a deep rabbit hole to fall down if you’re not careful.

One element that’s often overlooked is the filament spool; if it’s not rotating smoothly, the drag it puts on both the extruder and movement of the print head can cause difficult to diagnose issues. For his custom built printer, [Marius Taciuc] developed a very clever printable gadget that helps the filament roll spin using nothing but the properties of the PLA itself. While the design might need a bit of tweaking to work on your own printer, the files he’s shared should get you most of the way there.

All you need to do is print out the hubs which fit your particular filament spools (naturally, they aren’t all a standard size), and snap them on. The four “claws” of the hub lightly contact a piece of 8 mm rod enough to support the spool while limiting the surface area as much as possible. The natural elasticity of PLA helps dampen the moment that would result if you just hung the hub-less spool on the rod.

The STL files [Marius] has provided for his low-friction hubs should work fine for anyone who’s interested in trying out his design, but you’ll need to come up with your own method of mounting the 8 mm rod in a convenient place. The arms he’s included are specifically designed for his customized Prusa Mendel, which is pretty far removed from contemporary desktop 3D printer design. Something to consider might be a piece of 8 mm rod suspended over the printer, with enough space that you could put a couple spools on for quick access to different colors or materials.

Hackers have been trying to solve the spool friction issue for years, and as you might expect we’ve seen some very clever designs in the past. But we especially like how simple [Marius] has made this design, and the fact that you don’t need to source bearings to build it. If you’re thinking of giving this new design a shot, be sure to leave a comment so we know how it worked out for you.

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Old Meets New In 3D Printed Telegraph

March 12, 2019 by Tom Nardi 12 Comments

We often think of 3D printing as a way to create specific components in our builds, everything from some hard-to-find little sprocket to a custom enclosure. More and more of the projects that grace the pages of Hackaday utilize at least a few 3D printed parts, even if the overall build itself is not something we’d necessarily consider a “printed” project. It’s the natural progression of a technology which at one time was expensive and complex becoming increasingly available to the maker and hacker.

But occasionally we see 3D printing used not to create new devices, but recreate old ones. A perfect example is the almost entirely 3D printed telegraph system created by [Matt]. Projects like this help bring antiquated technology back to a modern audience, and can be an excellent educational tool. Showing someone a diagram of how the telegraph worked is one thing, but being able to run off a copy on your 3D printer and putting a working model in their hands is quite another.

[Matt] acknowledges that he’s hardly the first person to 3D print a telegraph key, but says that he’d never seen the complete system done before. The key is perhaps the component most people are familiar with from film and old images, but alone it’s really nothing more than a momentary switch. To actually put it to use, you need a telegraph sounder on the receiving end to “play” the messages.

The sounder is a somewhat more complex device than the key, and uses an electromagnet to pull down a lever and produce an audible clicking noise. In the most basic case, the coil is directly connected to the key, but in a modern twist [Matt] has added a MOSFET into the circuit so the electromagnet is triggered locally within the sounder. This prevents sparks from eroding the contacts in the key, and alleviates problems associated with current loss over long wire runs.

We’ve previously seen 3D printing used to revive vintage games which are no longer available such as “The Amazing Dr. Nim”, and how modern techniques such as additive manufacturing can help put World War II aircraft back in the air. While there was never much question that 3D printing would be a big part of our future, it would seem to be taking a fairly active role in preserving our past as well.

No, Your 3D Printer Doesn’t Have A Fingerprint

March 12, 2019 by Tom Nardi 103 Comments

Hackers and makers see the desktop 3D printer as something close to a dream come true, a device that enables automated small-scale manufacturing for a few hundred dollars. But it’s not unreasonable to say that most of us are idealists; we see the rise of 3D printing as a positive development because we have positive intentions for the technology. But what of those who would use 3D printers to produce objects of more questionable intent?

We’ve already seen 3D printed credit card skimmers in the wild, and if you have a clear enough picture of a key its been demonstrated that you can print a functional copy. Following this logic, it’s reasonable to conclude that the forensic identification of 3D printed objects could one day become a valuable tool for law enforcement. If a printed credit card skimmer is recovered by authorities, being able to tell how and when it was printed could provide valuable clues as to who put it there.

This precise line of thinking is how the paper “PrinTracker: Fingerprinting 3D Printers using Commodity Scanners” (PDF link) came to be. This research, led by the University at Buffalo, aims to develop a system which would allow investigators to scan a 3D printed object recovered from a crime scene and identify which printer was used to produce it. The document claims that microscopic inconsistencies in the object are distinctive enough that they’re analogous to the human fingerprint.

But like many of you, I had considerable doubts about this proposal when it was recently featured here on Hackaday. Those of us who use 3D printers on a regular basis know how many variables are involved in getting consistent prints, and how introducing even the smallest change can have a huge impact on the final product. The idea that a visual inspection could make any useful identification with all of these parameters in play was exceptionally difficult to believe.

In light of my own doubts, and some of the excellent points brought up by reader comments, I thought a closer examination of the PrinTracker concept was in order. How exactly is this identification system supposed to work? How well does it adapt to the highly dynamic nature of 3D printing? But perhaps most importantly, could these techniques really be trusted in a criminal investigation?

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OpenSCAD Gives You Parametric Boxes

March 11, 2019 by Brian Benchoff 39 Comments

OpenSCAD is one of the most powerful 3d modeling applications around. Its beauty is in its simplicity; if you need a box, you can just write the code for a box. If you need some bit of plastic to keep your 3D printer running, you can just write the code for that bit of plastic. Like all programming languages, OpenSCAD is only really powerful if you have a huge back-catalog of various components ready for reuse. That’s where [Mark]’s library for hinged boxes comes in handy. Every type of box you would ever want to create, from boxes with covers, magnet closures, or cases for your glasses is easily accessible with just a few lines of code.

The work presented here is an OpenSCAD script to generate two-piece hinged boxes, with rounded corners, a lid, interlocking rims, and optional snap fit, magnet, or screw closures. As you would expect from OpenSCAD, everything in this script is parametric. You can change any measurement or simply delete entire sections of the box.

The included examples consist of a small mini-Altoids tin-sized ‘Bee Box’ with a snap-fit lid. All of the relevant dimensions of the snap-fit lid are variables. Other examples include an eyeglass case and a box for small parts storage that interlock. If you have a few rolls of filament, a lot of time on your hands, and want to organize your workbench, you could do worse than checking out a few of these OpenSCAD boxes.

3D Printing Photos Is Slow But Awesome

March 5, 2019 by Lewin Day 13 Comments

Historically speaking, lithophanes are images made in porcelain with an etching or moulding process, in which an image is visible when backlit due to the varying thickness of the material. Porcelain isn’t the easiest thing to work with, but thankfully for those of us in the present, 3D printers are here to make everything better. [RCLifeOn] has been experimenting with printing lithophanes with great results.

The trick to printing a good lithophane is all in the preparation. It’s important to pick an image that looks good in greyscale, as this is not a process that reproduces color in any way. [RCLifeOn] then discusses the finer points of printer setup to get a nice looking print. Layer heights should be as small as possible to avoid visible vertical bands, and the lithophane should be printed in a vertical orientation, to avoid the print sagging due to a lack of support. Infill is best set to 100%. Most importantly, the printer should avoid crossing the outline of the print to avoid any stringy plastic artifacts spoiling the final product.

It’s a great guide that should help even a 3D printing novice create a great print with the minimum of fuss. A lithophane can make a wonderful gift and is also a good test of a printer’s capabilities, due to the fine detail required. We’ve seen them produced before too, in a wonderful lightbox configuration. Video after the break.

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Forget The Kiln, These Tiles Were Made On A Prusa

March 5, 2019 by Tom Nardi 22 Comments

Where does your mind go when you think of 3D printed parts? Running off hard to find replacement components? Maybe spinning up a bespoke electronics enclosure? Occasionally the little boat that you can compare to the little boats of others online? All reasonable enough answers. But thanks to the work of [Matthew Wentworth], you might have a new mental image to associate with the smell of melting PLA: decorative Portuguese Azulejo tiles.

As difficult as it might be to believe, the tiles you’re seeing here weren’t made on some exotic ceramic printer, but a standard Prusa i3 MK3. Well, at least they started on the 3D printer. As you might have guessed, there’s a bit more involved than that.

That said, the idea is actually quite simple. The printed “tile” is just the base plate, plus the raised elements that will eventually be seen on the surface. Everything else is just a void, which naturally saves a lot on printing time and material. Once the print is done, premixed spackling paste is pushed into all of the open areas and the top is made as smooth as possible with a putty knife. The filled tile is then left to dry for 24 hours or so.

Once it’s dried, you take the tile outside and sand the top down with a palm sander (or by hand, if you have the patience). This not only smooths out the spackle, but eventually will expose and then smooth the top parts of the print. Once everything is nice and silky, it gets sprayed with a semi-gloss clear coat to both protect it and give it that authentic looking shine.

[Matthew] actually created his designs based on images of real Azulejo tiles he found online, but really any sort of image that has raised elements like this could be made to work. If anyone out there decorates their home with 3D printed Jolly Wrencher tiles, you know where to send the pictures. Interestingly, these aren’t the first tiles we’ve seen made out of plastic, but we’ve got to admit these ones would look quite a bit more appealing on your kitchen walls.

PrintRite Uses TensorFlow To Avoid Printing Catastrophies

March 3, 2019 by Lewin Day 14 Comments

TensorFlow is a popular machine learning package, that among other things, is particularly adept at image recognition. If you want to use a webcam to monitor cats on your lawn or alert you to visitors, TensorFlow can help you achieve this with a bunch of pre-baked libraries. [Eric] took a different tack with PrintRite – using TensorFlow to monitor his 3D printer and warn him of prints gone bad – or worse.

The project relies on training TensorFlow to recognize images of 3D prints gone bad. If layers are separated, or the nozzle is covered in melted goo, it’s probably a good idea to stop the print. Worst case, your printer could begin smoking or catch fire – in that case, [Eric] has the system configured to shut the printer off using a TP-Link Wi-Fi enabled power socket.

Currently, the project exists as a plugin for OctoPrint and relies on two Raspberry Pis – a Zero to handle the camera, and a 3B+to handle OctoPrint and the TensorFlow software. It’s in an early stage of development and is likely not quite ready to replace human supervision. Still, this is a project that holds a lot of promise, and we’re eager to see further development in this area.

There’s a lot of development happening to improve the reliability of 3D printers – we’ve even seen a trick device for resuming failed prints.